Azhar
02/24/2026, 8:51 AMVapi Support Bot
02/24/2026, 8:52 AMassistantId for that campaign, as the assistant determines the voice used. This can be done using the Campaign API's update endpoint, but only if the campaign is not in progress or has ended.
Here’s a sample cURL request to update the assistant (and thus the voice) for a campaign:
bash
curl -X PATCH https://api.vapi.ai/campaign/<campaign_id> \
-H "Authorization: Bearer <token>" \
-H "Content-Type: application/json" \
-d '{"assistantId": "<your_new_assistant_id>"}'
Note: There is no direct "voice override" parameter; you must change the assistant to change the voice.
For more details, see the [Campaign Controller Update API documentation](https://docs.vapi.ai/api-reference/campaigns/campaign-controller-update).
Source:
- [Campaign Controller Update API documentation](https://docs.vapi.ai/api-reference/campaigns/campaign-controller-update)Chiranjeet Mishra
03/03/2026, 8:10 AM